I have been working on an example that detects repetitions by letter-number with the following JavaScript code.
But it's not working. The idea is that it detects that the combination A-1 is repeated; using a control matrix.
This is the items JSON structure:
{
letter: 'A',
number: '1',
},
{
letter: 'B',
number: '2',
},
{
letter: 'A',
number: '1',
},
{
letter: 'C',
number: '2',
},
And this is the code I am trying to:
var isRepeated = false;
var numItems = items.length;
if (numItems > 0) {
var item;
var letter;
var number;
var matrix = [[]];
for (var j = 0; j < numItems; j++) {
item = items[j];
letter = item.letter;
number = item.number;
if (matrix[letter][number] == undefined) {
matrix[letter][number] = true;
} else {
isRepeated = true;
break;
}
}
}
matrix[letter][number]
You're trying to access elements of an array using string keys but arrays use integer indexes
Here's an alternative if you just want to know if something is repeated
const props = [{
letter: 'A',
number: '1',
},
{
letter: 'B',
number: '2',
},
{
letter: 'A',
number: '1',
},
{
letter: 'C',
number: '2',
},
]
const didRepeat = (array) => array.some(((hash) => ({letter, number}) => {
const key = `${letter}_${number}`;
if (hash.has(key)) return true;
return hash.add(key), false;
})(new Set()))
console.log(didRepeat(props))